1. Field of the Invention
The present invention relates to a portable terminal device which has an openable and closable part as well as to an open/close detector which detects the opening and closing of the part.
2. Description of the Related Art
Conventionally, various portable terminal devices such as folding phones are equipped with an open/close mechanism such as a folding mechanism that contains an open/close detector which detects the opening and closing of the open/close mechanism.
For example, Japanese Reference Nos. 9-166405, 2002-125025 and 2002-204294 disclose a structure for use in a foldable device, such as a folding phone, equipped with a magnet on one of the parts which face each other when the device is folded, and a magnetic sensor on the other part, so that the magnetic sensor will detect magnetic force of the magnet when the device is folded.
FIGS. 1 and 2 are schematic diagrams showing an open/close detector disclosed in the three above-cited Japanese references, with FIG. 1 showing the folding phone when it is open and FIG. 2 showing the folding phone when it is closed.
The folding phone 10 shown in FIGS. 1 and 2 consists of a lower part 11 and an upper part 12 pivotably supported by the lower part 11. The upper part 12 folds in the direction of arrow A in FIG. 1 and unfolds in the direction of arrow B with respect to the lower part 11. The lower part 11 contains a circuit board 112 in its case 111. A magnetic sensor 113 is attached securely to the circuit board 112. The upper part 12 has a magnet 122 attached securely to a position in the case 121 which faces the magnetic sensor 113 when the folding phone 10 is folded (see FIG. 2).
FIGS. 3 and 4 are explanatory diagrams illustrating the principle of open/close detection of the folding phone shown in FIGS. 1 and 2. FIG. 3 shows a case in which the distance “a” between the magnetic sensor 113 and magnet 122 is sufficiently large while FIG. 4 shows a case in which the distance “a” between the magnetic sensor 113 and magnet 122 is sufficiently small.
When the magnet 122 is away from the magnetic sensor 113 as shown in FIG. 3, the magnetic sensor 113 cannot detect the magnetic force of the magnet 122, and detects only that the upper part 12 of the folding phone 10 is away from the lower part 11 (i.e., the folding phone 10 is open). On the other hand, if the magnet 122 is close enough to the magnetic sensor 113 as shown in FIG. 4, the magnetic sensor 113 detects the magnetic force of the magnet 122 and detects that the upper part 12 is close enough to the lower part 11 (i.e., the upper part 12 is folded over the lower part 11 (the folding phone 10 is closed)).
FIG. 5 is a schematic diagram showing a flip phone equipped with a conventional open/close detector.
The flip phone 20 shown in FIG. 5 consists of a main part 21 and a flipper 22 pivotably supported by the main part 21. The flipper 22 opens and closes with respect to the main part 21 in the directions of arrows C and D.
The main part 21 contains a circuit board 212 in its case 211. A magnetic sensor 213 is mounted on the circuit board 212. Within the case 221 of the flipper 22, a magnet 222 secured to the case 221 is attached securely to a position which faces the magnetic sensor 213 when the flipper 22 is closed.
With this flip phone, again the opening and closing of the flipper 22 is detected according to the principle described with reference to FIGS. 3 and 4.
FIG. 6 is a schematic diagram of a sliding phone equipped with a conventional open/close detector while FIG. 7 is a sectional view taken along line X—X in FIG. 6.
The sliding phone 30 in FIG. 6 consists of a main part 31 and sliding part 32. The sliding part 32 fits over the main part 31 as shown in FIG. 7 and can slide along the main part 31 in the direction perpendicular to the paper in FIG. 7, i.e., in the directions of arrows E and F in FIG. 6.
The main part 31 of the sliding phone 30 contains a circuit board 312 in its case 311. A magnetic sensor 313 is attached securely to that position of the circuit board 312 with which the sliding part 32 overlaps when the sliding part 32 is closed, i.e., when the sliding part 32 slides in the direction of arrow F in FIG. 6. Also, within the case 321 of the sliding part 32 of the sliding phone 30, a magnet 322 is attached to a position which faces the magnetic sensor 313 when the sliding part 32 is closed.
With this sliding phone, again the opening and closing of the sliding part 32 is detected according to the principle described with reference to FIGS. 3 and 4.
Although not shown, another example of a cell phone equipped with an open/close mechanism is a cell phone consisting of an upper part and a lower part which pivots around a pivot shaft perpendicular to the front face of the upper part and equipped with a so-called turn-type open/close mechanism in which the lower part turns 180 degrees between a closed state in which the lower part covers the front face of the upper part completely and an open state in which the lower part reveals the front face of the upper part, as shown in Japanese Reference No. 2002-344592.
Although the configuration which is disclosed in and the first three above-cited Japanese references detects opening and closing by means of a magnetic sensor attached to one part and a magnet attached to the other part is applicable to various types of cell phone and a wide range of other portable terminal devices as described with reference to FIGS. 1 to 7, since the magnetic sensor and magnet, which are contained in different cases, must be disposed in opposing relation to each other when the phone is closed, there is the problem that extra man hours are required for position adjustment. There is also the problem that dropping the device, or the likes may cause misalignment between the magnetic sensor and magnet, resulting in detection failure. With this detection mechanism, the magnetic sensor and magnet align in the thickness direction of the closed cell phone in a closed state. This makes it necessary to internally mount the magnet using a dual structure, increasing the thickness of the closed cell phone because of a complicated magnet-fastening structure and the like, and thus goes against the demand for thickness reductions.